Selective Growth of Microscale GaN Pyramids on Apex of GaN Pyramids

Abstract

We report on the growth and characterization of microscale GaN structures selectively grown on the apexes of hexagonal GaN pyramids. SiO 2 near the apex of the hexagonal GaN pyramids was removed by an optimized photolithography process and subsequently subjected to selective growth of micro scale GaN structures by metal organic vapor phase epitaxy (MOVPE). The pyramidal GaN microstructures which have semi-polar f1101g facets, were formed only on the apexes of lower GaN pyramids. The size of the selectively grown micro GaN structures was easily controlled by the growth time. Reduction of the threading dislocation density was confirmed by transmission electron microscopy (TEM) in the selectively regrown micro GaN structures. However, stacking faults developed near the edge of the SiO 2 film because of the roughness and nonuniform thickness of the SiO 2 film. #

Selective Growth of GaN Rods on the Apex of GaN Pyramids by Metal Organic Vapor Phase Epitaxy

“…The PR was partially removed only on top area of the hexagonal GaN pyramids with optimized conditions of UV light exposure and development time. 12) Au (5 nm) was deposited by e-beam evaporator after partial wet etching of the SiO 2 film on top area of the hexagonal GaN pyramids. After the conventional lift-off process, the metallic Au was remained only on the apex of the hexagonal GaN pyramids and the sample had been taken back to the MOVPE reactor for the second selective growth of GaN rods by using of Au as a catalyst.…”

Characterization of GaN microstructures grown by plasma-assisted molecular beam epitaxy

“…The micropyramid and semi-polar GaN were grown and characterized by many groups with various techniques. [9][10][11][12][13] Recently, we are able to grow c-plane (0001) wurtzite GaN microdisks and micropyramids on LiAlO 2 substrate by plasma-assisted molecular beam epitaxy (MBE). 5 The surface polarity of c-plane GaN microdisk and micropyramid generates a spontaneous polarization field at top surface, as shown in Figs.…”